Heat transmitting element



March 29, 1938. R POOLE 2,112,743

HEAT TRANSMITT ING ELEMENT Filed Aug. 4, 1954 Inventor: Ralph Poole,

by u -2M4 S Attor'neg.

Patented Mar. 29, 1938 UNITED STATES PATENT OFFICE HEAT TRANSMTTIN GELEMENT York Application August 4, 1934, Serial No. 738,520 In GreatBritain August 15, 1933 2 Claims.

This invention relates to heat-transmitting elements for effectinginterchange of heat between fluids in radiators, coolers, heaters,condensers and like surface heat-exchange apparatus.

The invention has for an object to provide an improved and economicalconstruction of heattransmitting elements offering relatively largecontact surfaces.

In the improved construction according to the present invention aheat-transmitting element for effecting the interchange of heat betweenfluids in radiators, coolers, heaters, condensers and like surfaceheat-exchange apparatus comprises a plate-like metal member, hereinreferred to as the foundation member, and at least one but preferably aplurality of perforated or openwork or gauze members of goodheat-conducting material such as copper or steel, which member has ageneral surface which is bowed away from the surface of the foundationmember and has its bowed edges secured to said foundation member in goodheat-conducting relationship therewith as by welding, soldering, or thelike, so as to form an openwork or perforated hollow gill for thefoundation member. In use, the apertures or perforations in the hollowgill will give rise to eddies or cross-jets in the fiuid'coming intocontact with the funclation member on the side thereof at which the gillis disposed. Moreover, particularly where 30 gauze is employed for theconstruction of the gills, the very extensive heat-conducting surfacepresented to fluid by the interwoven fibres or strands of the gauzeensures more efficient heat transfer through the element.

5 For a better understanding of what I believe to be novel and myinvention, attention is directed to the following description and theclaims ap- I pended thereto in connection with the accompanying drawing.

40 In the drawing, Figs. 1, 2, 3, and 6 illustrate differentconstructions of heat-transmitting elements in accordance with myinvention, and Figs. 4, 5, 7, and 8 illustrate different forms ofsurface heat-exchange apparatus employing heat-trans- 45 mittingelements in accordance with my invention.

The arrangement of Fig. 1 comprises a metal plate l0, hereafter referredto as the foundation plate, and a corrugated openwork or gauze sheet 50I l of good heat-conducting material such as copper or steel. Thecorrugated sheet II is secured in 'good heat-conducting relationshipwith the plate I0 by means of fused metal along the troughs of thecorrugations so as to form a series of hol- 55 low gills l2 for thefoundation plate l0. 'Preferably the gauze employed is of the typehaving multitudinous fibres or strands interwoven in relatively finemesh. The connection of the corrugated sheet H with the foundation plateI0 is improved in the present arrangement by the 5 provision ofstiffening ribs [4 along the troughs of the corrugations, which ribs aresecured to said troughs and the foundation plate by welding.

In the form shown the plate I0 is also provided on the opposing surfacewith similar hollow gills 10 I5 formed by a corrugated openwork or gauzesheet l6 secured to the plate l0 along the troughs of the corrugation bymeans of stiffening ribs l1 and fused metal such as welds. As will beevident, instead of employing a single sheet which is corl5 rugated toform the hollow gills, the same effect is obtained by the provision of aplurality of separate smaller sheets or strips, each of which is bowedto the shape assumed by an individual corrugation and which members aredisposed in par- 20 allel rows on the foundation plate and individuallysecured to the plate along their bowed edges.

In the form illustrated in perspective in Fig. 2, the heat-transmittingelement comprises a metal tube l8 and a tubular envelope IQ of openworkor gauze made of copper or other good heat-conducting material. Theopenwork or gauze envelope is substantially elliptical in cross sectionand embraces the tube l8 as shown and is secured in good heat-conductingrelationship therewith at opposite ends of a diameter of the tube bymeans of welds 20 and 2 I, extending longitudinally of the tube. Theportions of the gauze intermediate the welding seams are spaced awayfrom the surface of the tube 18 to form hollow gills 22 5 and 23. Theenvelope 19 may be formed from a single sheet of gauze material bent tothe desired shape.

In the form illustrated in perspective in Fig. 3, which is amodification of the tubular type of heat-transmitting elementillustrated in Fig. 2, the element comprises a metal tube 24 and aspiral 25 of copper or other good heat-conducting materail in strip orribbon form, which spiral embraces the tube 24. The individual turns ofthe spiral 25 are elliptical and are secured to the tube 24 atdiametrically opposite points by welds 26. The line of the welds extendslongitudinally of the tube. Intermediate the parts at which the spiralis secured to the tube 24 it is spaced away from the surface of the tubeso that the tube is in effect provided with two openwork sheets forminghollow gills 21 and 28 corresponding to the gills 22 and 23 in Fig. 2.

Referring now to the arrangement of Fig. 4,

" showing diagrammatically a section through a surface heat-exchangeapparatus which may be included in a fluid circulating system foreffecting the interchange of heat between fluids, said apparatuscomprises three heat-transmitting ele- 'ments 29, 30 and 3| disposed inparallel spaced relationship. These elements are constructed asillustrated in and described with reference to Fig. 1. Theintermediately disposed element 30 is provided with hollow gills 32 and33 on both sides, whereas the elements 29 and 3! are provided withhollow gills 34 and 35 respectively on one side only. The space betweenthe foundation plates of the elements 29 and 38 forms a duct for one ofthe circulating fluids and the space between the foundation plates ofthe elements 30 and 311 forms a duct for the circulation of the otherfluid. Said fluids may be circulated either in the longitudinaldirection of the hollow gills or transversely thereto. The sheets ofopenwork or gauze forming the gills 34 and 32 respectively are spacedapart to form intervening spaces 34a.

Referring now to Fig. 5, which is a sectional view of a totally encloseddynamo electric machine provided with a cooling system in accordancewith my invention, said machine has a rotor 36 and a stator 31 with ayoke 38. The machine has an inner casing defined by end walls 39 and 4tand a cylindrical wall 4i secured at its end to said end walls, and themachine has an outer casing defined by a plate 42 spaced from the endplate 39 and another circulation wall 43 encircling in spaced relationthe aforementioned wall 4i. As will be readily seen from the drawing,the yoke 38 and the walls 4! and 43 form two concentric channels orducts or passages, a channel 44 communicating at its ends with theinterior of the machine and a channel 45 communicating at both ends withthe atmosphere. A fan 48 secured to the rotor shaft serves forcirculating air or like medium through the channel 44 and another fan 41secured to the rotor shaft and disposedbetween the walls 39 and 42serves for circulating air or like medium through the channel 45. Thetransmission of heat from the medium in the channel 44 to the medium inthe channel 45 is considerably improved by the provision of corrugatedsheets of gauze 48 and 49 secured to opposite sides of the cylindricalmember 41!, which member corresponds to the foundation plate in ofFig. 1. Said sheets of openwork or gauze are secured to the cylindricalmember 4| by means of fused metal. The openwork or gauze sheet 48forming the hollow gills disposed in the channel 44 through which theenclosed air or medium is circulated is preferably dipped, coated orsprayed in viscous liquid, such as oil, whereby said sheets may servethe additional purpose of freeing the circulating enclosed stream fromdust particles generated during prolonged operation of the machine.

In Fig. 6, I have'shown a perspective view of another constructionalform of heat-transmitting element according to my invention. In thisform the metal tube 50 is provided with a plurality of hollow gills 5|,52, 53, and 54 extending in the direction of one diameter. The enclosingwalls of each gill are of gauze or like openwork sheet of goodheat-conducting material such as copper. The several gills may be formedfrom a single openwork or gauze sheet which is bent to the proper shapeand welded to the tube 50 at opposite ends of two diameters of thetubes. In the present instance the sheet is secured to the tubes by fourwelds 55, 56, 51, and 58. The welding seams extend along the tubethroughout the whole width of the sheet. By the adoption of thisconstructional form, an advantageous arrangement of the elements toconstitute a cooler becomes available in that a number of suchheat-transmitting elements may be assembled fairly closely to oneanother with the mesial planes of the hollow gills lying insubstantially parallel planes transverse to the direction of flow of oneof the fluids indicated by an arrow 59. It will be appreciated that theother fluid or fluids flow through the tube or tubes 58.

Referring now to Fig. 7, which illustrates diagrammatically anadaptation of heat-transmitting elements according to the invention inthe construction of a cooler for oil ring journal bearings, the bearingcomprises a liner for supporting a shaft iii and secured to a casing 62which latter forms a container 63 for oil or like lubricant. Lubricantis conducted to the bearing surface by a lubricating ring 64 held on theshaft and projecting into the container 63. A tube 65, through which acooling medium is conducted, is disposed in the container 63. This tube65 according to my invention is provided with perforated or openworkhollow gills 66 and ti disposed on opposite sides of the verticaldiameter of the tube 65. These gills may be formed, as described above,by securing individual bowed members of gauze or openwork sheets to thetube. In this case, however, the bowed members are deformed to the shapeshown in the drawing so that the gills 6B and 61 form a trough or gutterB8. The tube 65 and the gills 66 and iii are entirely immersed in thelubricant and the arrangement is preferably such that the oillubricating ring 64 projects into the space of the gutter 68. Duringoperation, oil discharged from the ends of the bearing flows through thegills, where it is cooled, into the gutter 68. The movement of thelubricating ring 64 assists the cooling effect in that the ring effectscontinued motion of the lubricant within the gutter 68.

In Fig. 8, I have shown an adaptation of heattransmitting elements inaccordance with the invention in the construction of radiators forcooling the engine or working fluid in aircraft or other vehicles. Inthe present instance the radiator is formed by a Wing of an airplane. Itcomprises an outer shell 10 and an inner shell ll between which fluid tobe cooled, for instance water from the cooling jacket of a combustionengine, is caused to pass. The outer and inner shells l0 and IIrespectively are constructed with an air foil section and the outersection is provided on its external surface with a plurality of hollowgills 12 formed as illustrated in and described With reference to Fig. 1and disposed with their mesial planes extending substantially at rightangles to the line of air foil section. In the present instance I havealso provided a shield 13 in front of the radiator, that is in thedirection of airplane travel. The shield has a number of hinged flaps 14for controlling the amount of cooling air at different relative airspeeds.

Having described the method of operation of my invention, together withthe apparatus which I now consider to represent the best embodimentsthereof, I desire to have it understood that the apparatus shown is onlyillustrative and that the invention may be carried out by other means.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

1. A heat-transmitting element for effecting the interchange of heatbetween fluids in radiators, coolers, heaters, boilers, condensers andthe like surface heat-exchange apparatus comprising a plate member,gauze sheets of good heat-conducting material corrugated to form troughson each side of the plate member, and means including reinforcing ribsuniting the troughs with the plate member, the gauze sheets on oppositesides of the plate member being symmetrically arranged so that thetroughs and reinforcing ribs contact portions of the plate memberdirectly opposite each other and thereby effect good heat-transmissionfrom one side of the plate member to the other side thereof.

2. A heat-transmitting element for effecting the interchange of heatbetween fluids in radiators, coolers, heaters, boilers, condensers andthe like surface heat-exchange app: ratus comprising twoparallel-arranged plate members, corrugated gauze sheets secured to thesurfaces of the plate members facing each other and arranged to formtroughs and gills with the gills of the gauze sheet on one plate memberprojecting into the troughs of the gauze sheet on the other platemember.

RALPH POOLE.

